We are given the following equation :
[tex]{:\implies \quad \sf P=2L+2w}[/tex]
And we need to solve for w, so let's start :
[tex]{:\implies \quad \sf P=2L+2w}[/tex]
Now, transpose 2L to LHS ;
[tex]{:\implies \quad \sf P-2L=2w}[/tex]
[tex]{:\implies \quad \sf 2w=P-2L}[/tex]
[tex]{:\implies \quad \boxed{\bf{w=\dfrac{(P-2L)}{2}}}}[/tex]
Hence, Option a) is correct
